Touch sensitive devices allow a user to conveniently interface with electronic systems and displays by reducing or eliminating the need for mechanical buttons, keypads, keyboards, and pointing devices. For example, a user can carry out a complicated sequence of instructions by simply touching an on-display touch screen at a location identified by an icon. In many touch sensitive devices, the input is sensed when a conductive object in the sensor is capacitively coupled to a conductive touch implement such as a user's finger. Such devices measure capacitance at multiple locations due to the touch disturbance, and use the measured capacitances to determine touch position.
In some applications, multiple touch inputs are applied at the same time, for example from multiple users in a multiplayer game or from a single person using a virtual keyboard or similar interface. Such applications benefit from the accurate discrimination of multiple simultaneous touches so that the touch position for each input can be determined to trigger appropriate actions in the application.